The present invention relates to a control system for controlling functionality of an electrically powered vehicle, in particular but not exclusively a wheelchair.
Powered wheelchairs typically have customised settings for a particular user, for example a maximum acceleration to limit the forces upon a user's body. Known wheelchair control systems offered generally comprises a plurality of modules each responsible for the control of a specific aspect of the wheelchair operation, for example lighting control, seating control and the like.
The programming of the modules with specific user settings is a time consuming process. In some cases it can represent a considerable investment by a wheelchair distributor or provider, but is desirable for the comfort and safety of the user.
The modules' programmable data is typically stored in non-volatile memory such that the data will be retained if the power is lost. This allows for the system to remain configured if batteries are replaced or if the wheelchair is dismantled for transportation in a vehicle.
From a functional point of view it may be considered desirable for each module to store its own settings internally. This simplifies the system management since no other modules need to be involved, but it does have two drawbacks, the first regarding module replacement and the second regarding systems containing more than one module of the same or similar type.
The primary advantage of a module storing its own settings is that no other modules need interpret the size or meaning of the data stored by that module. Effectively, the module is self-contained. If the manufacturer develops a new version of the product with extra features, the new module can fit into an existing system, and the user can take advantage of the new features, with no need to change any of the existing modules in any way.
If a module develops a control system fault, it may be difficult to repair in situ. Instead, where the service personnel identify a faulty module, they will replace it and return the faulty module to a service centre. If the settings for the faulty module reside within the module, it can be a time-consuming task to copy the settings and program them into the replacement module. The procedure may also be susceptible to human error. Hence it is desirable for the system to store the settings for each module, and for the settings for a replacement to be changed automatically.
Where systems contain more than one module, it may be desirable for some of their programmable settings to be common. Separate storage for each module would work against this, requiring each module to be set up independently. It is possible to work around this using a more powerful programming tool, but it is better to establish a common data source for identical modules.